title: Systematic review on daily vitamin B12 losses and bioavailability for deriving recommendations on vitamin B12 intake with the factorial approach.
abstract: OBJECTIVE
  To systematically review the literature on daily losses and bioavailability of vitamin B12. These estimates could be used for deriving recommendations on vitamin B12 intake for adults and elderly.
  
  
  METHODS
  We identified publications on daily vitamin B12 losses (July 2011) and publications on the bioavailability of vitamin B12 from foods or diets (June 2010) in MEDLINE, EMBASE and the Cochrane Library.
  
  
  RESULTS
  A pooled analysis of five studies (52 subjects) showed that 0.13 ± 0.03% of the total body store is lost per day. Absorption of vitamin B12 ranged from 4.5 (dose of 38 µg from consumption of liver) to 83% (dose of 3.0 µg from consumption of mutton meat). Data from eight studies including 83 subjects suggested that the amount of vitamin B12 absorbed from food (Ai) increased with increasing doses of vitamin B12 (Di) as described by the equation: ln(Ai) = 0.7694 * ln(Di) - 0.9614.
  
  
  CONCLUSIONS
  Daily vitamin B12 losses in apparently healthy adults and elderly probably range from 1.4 to 5.1 µg. Vitamin B12 intakes needed to compensate for these losses seem to range from 3.8 to 20.7 µg. More evidence is needed on the relationships between biochemical markers of vitamin B12 status, vitamin B12 body store and long-term health outcomes to evaluate whether current recommendations on vitamin B12 intake (1.4-3 µg) need to be changed.
authors.affiliation: Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands. esmee.doets@wur.nl
authors.forename: Esmée L
authors.initials: EL
authors.lastname: Doets
authors.forename: Paulette H
authors.initials: PH
authors.lastname: In 't Veld
authors.forename: Anna
authors.initials: A
authors.lastname: Szczecińska
authors.forename: Rosalie A M
authors.initials: RA
authors.lastname: Dhonukshe-Rutten
authors.forename: Adrienne E J M
authors.initials: AE
authors.lastname: Cavelaars
authors.forename: Pieter
authors.initials: P
authors.lastname: van 't Veer
authors.forename: Anna
authors.initials: A
authors.lastname: Brzozowska
authors.forename: Lisette C P G M
authors.initials: LC
authors.lastname: de Groot
mesh_terms: D000328:Adult; D000368:Aged; D001682:Biological Availability; D006801:Humans; D018673:Nutrition Policy; D009751:Nutritional Requirements / Q000502:physiology*; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000592:standards; D014806:Vitamin B 12 Deficiency / Q000378:metabolism*
chemical_list: D014805:Vitamin B 12